:root{color-scheme:dark;--ink:#e7eeef;--muted:#91a4ae;--line:#a4c5d326;--accent:#e7c58e;--cyan:#96d9e7;--sky:#050a12;font-family:-apple-system,BlinkMacSystemFont,'PingFang SC','Microsoft YaHei',sans-serif;color:var(--ink);background:var(--sky)}
*{box-sizing:border-box}body{margin:0;font-size:15px;line-height:1.85;background:radial-gradient(ellipse at 75% 3%,#1a253647,transparent 35%),radial-gradient(ellipse at 12% 60%,#12314120,transparent 40%),var(--sky);min-height:100vh}a{color:inherit;text-decoration:none}button{font:inherit;color:inherit;cursor:pointer}a,button{-webkit-tap-highlight-color:transparent}a:hover{color:var(--accent)}a:focus-visible,button:focus-visible{outline:2px solid var(--accent);outline-offset:5px}[hidden]{display:none!important}h1,h2,h3,p,figure{margin:0}h1{font-weight:430;line-height:1.5;font-size:clamp(25px,2.4vw,36px);letter-spacing:.04em}h2{font-size:20px;line-height:1.6;font-weight:500;margin:44px 0 20px}h3{font-size:15px;font-weight:500;margin-bottom:8px}p+p{margin-top:14px}strong{font-weight:550;color:var(--ink)}.stars{position:fixed;inset:0;z-index:-1;opacity:.46;pointer-events:none;background-image:radial-gradient(1px 1px at 10% 13%,#b6d4df 50%,transparent),radial-gradient(1px 1px at 83% 32%,#91b4c7 50%,transparent),radial-gradient(1px 1px at 39% 81%,#b6d4df 50%,transparent),radial-gradient(1px 1px at 56% 57%,#b6d4df 50%,transparent);background-size:263px 271px,383px 307px,217px 347px,491px 421px}
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#reading-layout{display:grid;grid-template-columns:205px minmax(0,1fr);gap:48px;padding-top:22px}.topic-nav{display:flex;flex-direction:column;align-self:start;position:sticky;top:30px;border-right:1px solid var(--line);padding:0 24px 30px 0;gap:6px}.topic-nav a{font-size:13px;line-height:1.75;color:var(--muted);padding:8px 10px;position:relative}.topic-nav a[aria-current=page]{color:var(--accent)}.topic-nav a[aria-current=page]:before{content:'';width:3px;height:3px;position:absolute;top:18px;left:0;background:var(--accent);border-radius:50%}.topic-nav .all-topics{color:var(--ink);font-size:13px;margin-bottom:20px;padding-left:0}.pages{min-width:0;max-width:990px}.topic-heading{padding-bottom:25px;border-bottom:1px solid var(--line);margin-bottom:30px}.topic-heading .eyebrow{margin-bottom:12px}.topic-heading p:not(.eyebrow){margin-top:16px}.split{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:38px;align-items:start;margin:24px 0 32px}.split.dominant{grid-template-columns:1.2fr 1fr}.key-copy{padding-top:22px}.key-copy h2{margin-top:0}.key-copy h3{color:var(--accent);margin-top:20px}.step-no{font-size:12px;color:var(--accent);font-weight:400;margin-right:16px;vertical-align:3px}.flow{margin:0;padding-left:22px}.flow li{margin:0 0 12px;padding-left:5px}.subtle,figcaption{color:var(--muted);font-size:13px;line-height:1.8}figcaption{margin-top:15px}figure{min-width:0}.wide-figure{margin:25px 0}.small-figure{max-width:560px;margin:35px auto}.worked{padding:18px 0 0}.worked .formula-trigger{font-size:22px}.method-row{border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:23px 0;margin:35px 0}.method-row p{display:inline;margin-right:16px}.text-link{color:var(--accent);font-size:14px}.mistakes{border-left:2px solid #e7c58e80;padding:4px 0 4px 16px;color:var(--muted);font-size:13px;margin-top:25px}.mistakes strong{color:var(--accent)}.notes-grid{display:grid;grid-template-columns:1fr 1fr;gap:26px 38px}.notes-grid p{font-size:14px;color:#b9c8cf}.notes-grid h3{color:var(--accent)}
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dialog{width:min(680px,calc(100vw - 32px));max-height:85vh;border:1px solid #a4c5d338;padding:34px 40px 38px;color:var(--ink);background:#0b1420;box-shadow:0 30px 130px #000b;border-radius:9px;overflow:auto}dialog::backdrop{background:#01050bc4;backdrop-filter:blur(7px)}dialog h2{font-size:22px;margin:0 35px 18px 0}dialog h3{color:var(--accent);font-size:13px;margin:25px 0 10px}.dialog-close{position:absolute;right:19px;top:16px;border:0;background:none;font-size:27px;color:var(--muted);width:36px;height:36px}#formula-display{font-size:27px;overflow:auto;padding:10px 0}#formula-display .katex-display{margin:0;text-align:left}#formula-display .katex{font-size:1em}#formula-symbols{display:grid;grid-template-columns:max-content 1fr;gap:12px 24px;margin:0;padding-bottom:7px}#formula-symbols dt{min-width:35px}#formula-symbols dd{margin:0;color:#b8c9d1;font-size:14px;line-height:1.75}dialog p{font-size:14px;color:#b8c9d1}body.modal-open{overflow:hidden}
.stars{z-index:0}.site-head,#knowledge,footer{position:relative;z-index:1}.atlas-heading{padding-top:8px}.constellation{height:440px}.cluster.gravity{bottom:2%}.central-node{top:37%}.formula-trigger{padding-right:8px;padding-left:2px}
.formula-legend{font-size:12px;color:var(--muted);line-height:2.1;margin:0 0 24px}.legend-box{border:1px solid #e7c58e99;color:var(--accent);padding:3px 8px;margin-right:5px;white-space:nowrap}.formula-math{display:block;width:max-content;max-width:100%}.formula-textbook .formula-math{border:1px solid #e7c58e99;padding:12px 17px;box-sizing:border-box}.formula-trigger.formula-textbook:after{display:none}#formula-display.textbook-display{border:1px solid #e7c58e99;padding:16px 20px;width:max-content;max-width:100%;box-sizing:border-box}
@media(min-width:1500px){#knowledge{padding-left:50px;padding-right:50px}.constellation{height:520px}}
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@media(max-width:760px){.site-head{padding:20px 22px;height:86px}.brand{font-size:12px;gap:9px}.phi{width:35px;height:35px;font-size:27px;line-height:31px}.back{font-size:11px}#knowledge{padding:0 22px;margin-top:5px}#reading-layout{display:block;padding-top:10px}.topic-nav{position:static;border:0;display:block;padding:0;margin-bottom:26px}.topic-nav a:not(.all-topics){display:none}.topic-nav .all-topics{display:inline-block;margin:0}.topic-heading{padding-bottom:22px;margin-bottom:26px}.split,.split.dominant,.graph-step{grid-template-columns:1fr;gap:20px}.key-copy{padding-top:0}.split figure{max-width:520px}.apparatus figure{max-width:440px}.notes-grid{grid-template-columns:1fr;gap:24px}.formula-trigger{font-size:25px}.formula-trigger.long,.worked .formula-trigger{font-size:20px}.solution .formula-trigger{font-size:18px}.diagram text{font-size:18px}.diagram .tick{font-size:16px}.tape-wide{min-width:700px}figure:has(.tape-wide){overflow-x:auto;padding-bottom:10px}.constellation{height:auto;display:flex;flex-direction:column;gap:28px;margin:40px 0 25px;padding-left:22px;border-left:1px solid #a4c5d32c}.network-lines{display:none}.central-node,.cluster{position:relative;left:auto;right:auto;top:auto;bottom:auto;transform:none;align-items:flex-start;background:none}.central-node{order:0;font-size:23px;padding:20px 0 24px}.central-node:before{position:absolute;left:-27px;top:30px}.central-node .halo{display:none}.observe{order:1}.derive{order:2}.gravity{order:3}.cluster{padding:0;gap:12px}.cluster a{font-size:16px;min-height:38px}.cluster a:before{display:none}.cluster a{padding-left:0}.cluster a i{opacity:1}.atlas-heading{padding:25px 0 0}.definition{font-size:16px}.atlas-heading h1{font-size:25px}h2{margin-top:34px}footer{padding:22px;letter-spacing:0}.small-figure{margin:25px 0}dialog{padding:30px 24px}#formula-display{font-size:22px}#formula-symbols{gap:10px 15px}#formula-symbols dd{font-size:13px}}
.distance-emphasis{border-left:2px solid var(--accent);padding:15px 22px;background:linear-gradient(90deg,#e7c58e0b,transparent);font-size:16px}.distance-emphasis strong{font-size:23px;line-height:2}.motion-path{max-width:880px;margin:25px auto 35px}.special-methods{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:26px;margin:25px 0 35px}.special-methods h3{color:var(--accent);font-size:16px}.special-methods p{font-size:14px}.special-graph-item{border-top:1px solid var(--line);padding-top:16px;margin-top:32px}.special-graph-item .quick-heading>span{font-size:12px;color:var(--muted)}.special-graph-item .split{gap:28px}.special-graph-item .formula-trigger{font-size:24px}.special-graph-item .diagram{width:100%}
@media(max-width:760px){.special-methods{grid-template-columns:1fr;gap:4px}.special-graph-item .quick-heading{display:block}.special-graph-item .formula-trigger{font-size:21px}.distance-emphasis{padding:12px 16px}.distance-emphasis strong{font-size:21px}}

/* Pursuit: two methods, shared position convention, and one unchanged v-t graph. */
.pursuit-convention{padding-left:18px;border-left:2px solid var(--accent);color:var(--muted)}
.pursuit-method .key-copy{padding-top:0}.pursuit-method .key-copy>p{font-size:14px}.pursuit-method .key-copy>.text-link{display:inline-block;margin-top:18px}
.pursuit-diagram .pursuit-roman{font-family:KaTeX_Main,serif}.pursuit-diagram{max-width:520px}
.pursuit-choices{display:flex;flex-wrap:wrap;gap:8px;margin:20px 0 14px}.pursuit-choices button{border:1px solid var(--line);border-radius:5px;background:transparent;padding:9px 11px;font-size:13px}.pursuit-choices button[aria-pressed=true]{color:var(--accent);border-color:var(--accent);background:#e7c58e0c}
.pursuit-result{min-height:110px;border-left:2px solid var(--accent);padding:10px 15px;background:#e7c58e06}.pursuit-result p{margin:0;font-size:14px}.pursuit-result strong{color:var(--accent);font-size:17px}
.pursuit-notes{border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:18px 0;margin-top:32px}.pursuit-notes summary{cursor:pointer;color:var(--accent)}.pursuit-notes .notes-grid{margin:24px 0 10px}
.pursuit-links{display:flex;flex-wrap:wrap;gap:28px;margin-top:24px}
@media(max-width:760px){#quick-pursuit .formula-trigger{font-size:19px}.pursuit-choices button{padding:10px 9px}.pursuit-result{min-height:108px}}